The present invention relates to lubrication flow management and containment systems for gas turbine engines.
Gas turbine engines generally use oil to lubricate and cool engine components during operation, though there is typically a need to separate the oil from certain regions of the gas turbine engine in order to reduce a risk of auto-ignition (i.e., oil fires) in relatively high-temperature areas. A typical prior art lubrication system utilizes a scavenge pump and a pressure pump, with the pressure pump delivering oil from a storage tank to desired engine locations and the scavenge pump delivering oil from these engine locations to the storage tank. A heat exchanger can be used to remove excess thermal energy from the oil before delivery to the storage tank. Both the pressure pump and the scavenge pump have fixed displacements and are both driven by a common drive shaft powered by engine operation at a fixed ratio via a gearbox. The pressure pump and the scavenge pump are stacked on top of each other on the drive shaft in order to save space and weight. Such a configuration is also considered desirable in the art because the use of a common drive shaft to power both the pressure pump and the scavenge pump ensures that a loss of power to or seizure of the scavenge pump will likewise halt operation of the pressure pump. This ensures that oil will not be pumped to engine locations and left there to accumulate, thereby causing flooding and an elevated risk of auto-ignition.
Air curtains are often used to contain oil within pressurized engine compartments. Oil that leaks out of such pressurized compartments can be problematic, for instance, with aerospace applications, leaking oil can be a nuisance by causing unpleasant odors in airplane passenger areas. It can be particularly difficult to maintain sufficient air curtains to contain oil in pressurized compartments across all engine operating conditions, particularly at relatively low-power settings (e.g., ground idle conditions) when scavenge pump operation does not generate adequate suction to maintain air curtains.